Can relay be used as a switch?

Can relay be used as a switch?

In addition, relays are also widely used to switch starting coils, heating elements, pilot lights and audible alarms. Relays are either electromechanical relays or solid-state relays. In electromechanical relays (EMR), contacts are opened or closed by a magnetic force.

How do you make a relay switch at home?

Construct the first circuit as follows:

1. Take one iron C-core.
2. Wind twenty turns of PVC-covered copper wire round one arm.
3. Connect one end to one terminal of the 1.5 V cell.
4. Connect the other end to the switch.
5. Complete the circuit by connecting the other end of the switch to the free terminal of the cell.

How many pins are used to connect the relay to the microcontroller?

Every relay normally consists three inputs pins such as VCC, GND and signal etc. Similarly, it also consists of three output pins such as NC (normally close), NO (normally open) and COM (common). Supply voltages are applied at VCC and GND pin which are normally 5V dc and signal voltages are applied at signal pin.

How are the relays connected to the microcontroller?

As it can be seen from the above circuit diagram, a ULN2003 is connected between the microcontroller and relays in order to drive multiple relays. The input is taken from the microcontroller pins and the output corresponding to each input is given to the 5 relays on the output.

How is a relay used in a circuit?

A relay is an electromagnetic switch which is used to switch High Voltage/Current using Low power circuits. Relay isolates low power circuits from high power circuits. It is activated by energizing a coil wounded on a soft iron core. For detailed working of relay please visit this page.

What kind of current does a microcontroller need?

The source or sink current of a pic microcontroller is just 25mA whereas an amount of 50 to 100mA current is required by a relay to function properly. Due to the presence of back emf, the negative voltages can reach the microcontroller and damage it. The above circuit is a relay driver circuit.

When does the transistor turn off the relay turns on?

When a logic 0 is given to the port pin of transistor then the relay turns off and when a logic 1 is given to it, the relay turns on. A diode 1N4007 is connected to protect the components against the back emf. This back emf is generated in the coil of the relay when the transistor turns off.